Precast cable trench



` Ital.

Dec. 2, 1958 A. slLvERsTElN ETAL 2,862,367

PRECAST CABLE TRENCH Filed Sept. 27, 1956 IN V EN TORS 9E /L nefs 71E/M TORNEYS,

PREcAsT CABLE TRENCH Alle Silverstein and Clifford H. Mons, cincinnati, ohio,

and Keith C. Andrus, Ludlow, Ky.

Application September 27,1956, Serial No. y612,538

3 Claims. (Cl. 61-41) While our invention was initially conceived forruse in power stations, substations and the like, to house electrical cables, it will be apparent that its utility is not so limited and the invention may be employed for any installation wherein a trench is required. We shall, however describe our invention as it applies to the laying of cables at a substation or a power station.

The present, generally accepted method of laying cables involves the digging of an open trench 21-24 inches deep and 18-24 inches wide. A layer of sand 'is then placed in the bottom of the trench, whereupon the cables are placed in the trench and supported on 'the sand. Additional sand is then put in the trench to cover the cables and the sand in turn covered by creosote soaked wooden planks positioned to lie several inches below the ground level. The remainder of the trench above the planks is then filled with dirt. Where additional cables are to be laid in the trenchor where repairs are required to the cables already laid, it will be evident that the workmen must dig up Vthe trench and this, of course, is a time consuming and difficult job. InV contrast to the practice characterized above, our invention contemplates the provision of precast trench forming sections which may be readily assembled in any required length or shape, the sections being provided with easily removable covers which lie at the ground level, thereby providing ready access to the cables simply by removing the cover members.

It is thus a principal object of our invention to provide a precast trench structure formed from prefabricated sectionswhich may be quickly and easily assembled at their place of use.

A further object of our invention is the provision of trench forming sections consisting essentially of supporting brackets, side walls, top slabs and bulkhead walls, all of which are of a size to be easily handled and readily fitted together in theiield.

A further object ofY our invention is the provision of trench forming sections which may be assembled together to form trench structures in which the sections are joined together at angles to one another, the same vbasic components enabling the user to provide elbow joints, T-joints, intersections and the like.

Still a further'object of our invention is the provision of a trench structure in which the component parts thereof are readily fitted together and yet do not require -permanent attachment one to the other, thereby permitting the structures to be disassembled and reused in a new location if so desired.-

-Still a further object of our invention is the provision of a trench forming structure of the character described wherein the covers or top members of the structure are United States Patent@ for engaging and removing them.

Patented Dec. 2, 1958 The foregoing, together with other objects of our invention which will appear hereinafter or which will be apparent to the skilled worker in the art upon reading these specifications, we accomplish by that construction and arrangement of parts of which we shall now describe an exemplary embodiment.

Referring now to the figures of the drawing wherein:

Figure 1 is a perspective view of a bracket member in accordance with our invention.`

Figure 2 is a perspective view of a side wall member in accordance with our invention.

Figure 3 is a perspective view of a top slab in accordance with our invention.

Figure 4 is a perspective view of a top slab viewed from beneath.

Figure 5 is a sectional view taken along the line 5-5 of Figure 3 and also illustrating slab engaging and lifting means.

Figure 6 is a perspective vieW of a modified form of bracket member.

Figure 7 is a perspective view of a bulkhead wall in accordance with` our invention.

Figure 8 is a perspective view with parts broken away illustrating a trench section formed in accordance with our invention.

Figure 9 is a vertical sectional view taken along the line 9 9 of Figure 8 and illustrating the field assembly of the sections.

Figure 10 is a fragmentary plan view with parts broken away illustrating an elbow joint construction.

Figure l1 is a plan View with parts broken away illustrating a T-joint construction.

Figure l2 is a plan view with parts broken away illustrating an intersection formed in accordance with our invention.

Figure 13 is a fragmentary perspective view with parts broken away illustrating the use of a bulkhead wall at the end of a trench section.

Referring first to Figure 1 of the drawings, we have therein illustrated a bracket member 1 which forms the basic supporting element for our trench structure. The bracket member comprises a base 1a having upstanding posts 2 and 3 spaced inwardly from the end edges of the base to provide supporting ledges 4 and 5. The ledges 4 and 5 will have a width substantially equal to the width of the side wall panels adapted to be supported thereon, such side wall panel being illustrated at 6 in Figure 2.l It will be understood, of course, that a separate side wall panel will be provided to form each side of the section. A top slab 7 is illustrated in Figure 3, the top slab being of a size to extend crosswise of the trench structure with its recessed shoulders 8 and 9 resting on the upper edges of the side wall slabs 6. Preferably, the under surface of the top slab will be cut away in the areas 10 and 11, with the elongated slots 12 and 13 extending through the slab and opening into the cut away areas.

The slots 12 and 13 provide a convenient means by which a key or tool 14 having an elongated head 15 may be passed through the slots and turned so as to permit the head 15 to engage the under surface of the slab in the cut away areas, thereby permitting the slab to Ybe readily lifted and handled.

The parts just described, which comprise the basic components of our trench sections, will be formed from reinforced precast concrete, preferably being formed from those types of concrete known to the trade as lightweight concrete. The various members will be suitably Vreinforced with the formed rod or bar stock to meet the requirements of use. In an exemplary embodiment, we havefound that precast members formed from concrete 'Weighing 98 pounds per cubic'fcct and ,suitably reinforced V"having a. thickness of' approximately 3-finches"are"higl 1 ly satisfactory. The overallldirnejnsions' .wilh 'of' cour Vrdepending upon the sizeofY trench'lstructurev'des1red,al

thoughit `will be apparent `that`the side wa'll members. may be formed in various standardized lengths'todit;thenormal conditionsof use. Thus, ina Atypical asseiirbly'fthe lengths ofthe side walls may -be standardizedat 60 inches,

40 inches and 2i) inches, withjcor'frierand joint' forming Walls of 32 inch lengths. "fSirnilarly, the/top slabsfmay be standardized'at 20 inch lengths, ,witl`26 inch ardf`29 Yinch` lengths for corner ,sectionv joints arid"th`e'f'lik exemplary dimensions have been'ut'ilizedwith'bracket rnembersnaving an Lall over length'fofZ feet`8 inches and an 'all over height of' 18 and `1/i inches.

An assembled trench section isillustrated in 'Figure 8.v`

As seen therein, 'the section comprisesa pairor bracket members at each end thereof, Vthe'bracket inemberssupporting side wall panels 6 which rests on the 'supporting ledges 4 and- 5 of the brackets with end edges fthe'side wall panels terminating intermediate the width' offthe base members 1. Thus the end of an adjacent wallj panel 6a (shown in dotted lines) may be brought into edge abutting relationship to the wall panel and thefabutti'ng, ends of the panels 6 and 6a supported by a single bracket /mer'nber. The top slabs 7 are then fitted in place crosswise of the section, inthe manner illustrated. v

Figure 9 illustrates the'manner in which the sections are installed in the field. As seen therein, the base 11a of the bracket member is ,iirst seated in .the bottom oran open ditch or trench 16 inthe bottom of which sand or other ill 17 has been placedto level the bracket members. The side panels 6 are then tted in placeon the ledges 4 and 5 with the inner surfaces of the side walls juxtaposed to the posts 2. and 3. 'The side walls are then hel'dlin,

within the side walls of the trench structfurefto'fornital Y floor, the sand covering the base portions ffthe bracket member. The service cables orfthe like 20 areV then laid on the sand in the mannerrillustrated; and 'the structure is completed by placing'the top slabs crosswise ofthe trench, the recessed shoulders l8 and@ of `the top slab's seating on the'upper edges of thefside wall panels 6. To

this end,'it willl be notedfthatthe upper edges of the side f wall panelsproject,upwardly' beyond the upper edgesof thepostsjland' by, a 'distanceequal to the depthof the recessed shouldersS and 9. lt will'be understood',.off.

course, 'that in positioning 'the bracket members, 'the'ir depth below the groundilevel will be such t'hatthe upper surfaces of 'the top slabs lie at or slightly above the ground level.

it will .be readily apparent from'the above that fthe trench may` be easily opened by vsimply inserting the 'tool 1stin the'slots of the top slabs, whereupon the top'fslbs may be removed to expose'the service cablesrfor repair or replacement. In addition, thetopslabs whenlirhplace will serve as a convenient cement walk. following thepa'th of the'various cables.

In order to obtain complete 'exibilityof the sections for forming elbow joints ,and the like, we'have' foun'df it desirable to provide a second'form 'of bracket member 21 which, as seen in Figure 6, is provided with supporting posts 22and 23 which extend inwardly from one side edge of the base member 24- but terminating short of the opposite side edge of the base so vas to provide a longitudinal supporting ledge 25. Thus, as seen inFigurelO,

an Velbow joint may be constructed by placingra pairof `the brackets 1 atright angles'to each other to formlthe trench being formed by means of a bracket member 21 `which will support a vshort wall secton'Z on its longitudinal edge 24, a second short wall section 27 forming the adjaient side of the corner joint. A special square cover slab 28 is provided to close the top of the joint.

Figure 11 illustrates the formation of a T-joint. As illustrated therein, three of the brackets 1 are arranged to form the ends of the three meeting sections, and a short wall section .26 isy utilizedto yclose the fourth side ofthe T-joint. AV suitably dimensionedcover slab .28 furnishes' the topifor the joint.

Figure l2 illustrates the formation of an intersection or crossythe constructionbeing substantially identical with that of Figure 11 .excepting in ythe use of a fourth bracket member 1 to complete the intersection. In this instance the intersection is covered by means of a top slab 29 similar to the cover member 28.

Figure 13 `illustrates how `a trenchsection Inaybetterminated'in an erd wall. "To this end, a bracket member 21 is providedr at theen'dfofthe section with.ihe,.l.0n

gitudinal "supporting, ledgek 25 outer-most. A .bulkheadA or end wall 30 (Figure7)rwhi'ch may have an openingl 31 therein is supported on the 'longitudinalledge 25.7and serveskto close therend of the trench. The opening-,'.l permits ,cables such Vaslthe cables 20aillustra'tedin., dotted 'lines toproject therethrough, as whereit is .de's'iredgto extend one or more ofthe cables'beyon'dthe co'nnesf the trench. lOf courseif `de'sired,the endof-the trench maybe vclosed by asolid'bulkhe'ad wall.

From the' foregoing it should be-apparent'-that .;our trench structure provides a convenient, inexpensiveand easy to handle unit which may be readily assembled. and

disassembled and which does notrequirey the permanent joining together yof the parts.. -Modications maybe made in our invention without departing fromthespirit of it'andv we do not intended to'limit ourselves excepting -mthe manner set forth in the claims whichfollow.

Having1thusdescribed our inventionin Van Vexemplary embodiment', whatv we desire to secure and proteetgby 'Letters Patent is:

1. A-precast cable trench structure comprising, in combination, a series of bracketsjarranged crosswise inspaced apart generallyv parallel relation inl an open trench, each of said'brackets having a horizontally Idisposed lbase and a -pair of vertical posts extending upwardly fromM the base, saidpostsbeing of a" height suflicient to support side wall slabs in verticalposition ,andspaced inwardly from Ythev end'edges ofthe base Vto defineoutwardly extending Lslabs'supporting ledges atthe ends kof the brackets, the

bases of thesaid brackets being of a width sufieientt'o lbe self supporting, generally rectangular wall forming slabs extendingfbetween the approximate midpoints of `corresponding ledges of adjacent barckets, said lslabs havlng` the endportions of their bottom Yedges Ysupported on vsaidledges yand their inner surfaces contactingandsupported by the outermost surfacesof said vertical posts,

and cover members `extending crosswis'e of the trench'be- -tweenopposed wall slabs,` saidl cover members having recessed shoulders `ati'theirends seated u ponthe upper Yedges-of said-slabs, said brackets,.wall slabsl and-cover baseand a pair ofl verticali posts extending upwardly from thebase, saidposts being ofa height suicient'to sup- ;,port sidewall slabs Virrvertical position andfrspacled inwardlylboth from theend edges Vof jthejbase andfrom jone. side edge Vthereof to define outwardly extending'slab supporting iled'ges at' the vends of the bracket Aand a forwardly extending bulkhead supporting ledge along a side of the bracket, said base being of a sufcient width to be self supporting, and a bulkhead wall of a size to extend between said pairs of posts with end portions of the rear surface of the bulkhead contacting and supported byl said posts and the lower edge of the bulkhead supported on said forwardly extending ledge.

3. The cable trench structure claimed in claim 2 wherein said wall forming slabs are of uniform height, being slightly higher than said Vertical posts, and are provided in a plurality of predetermined lengths, whereby the length of the trench structure may be readily varied to accommodate it to specified lengthwise dimensions.

References Cited in the le of this patent UNITED STATES PATENTS Lappin Dec. 2, Stovall Aug. 20, Stovall Dec. 2, Kenway Ian. 18, Steffens May 22, Fender Dec. 11, Amsden May 12, Fredenhagen May 31, Haase Apr. 25, Butler Aug. 19,

FOREIGN PATENTS Great Britain Dec. 14, 

